Chikoy (Russian: Чикой, Mongolian: Цѳх гол, Buryat: Сүхэ гол) is a river in Zabaykalsky Krai and the Buryat Republic in Russia, which partially flows along the Russo-Mongolian border. It is a right tributary of the Selenga River. The length of the Chikoy is 769 kilometres (478 mi). The area of its basin is 46,200 square kilometres (17,800 sq mi). The river usually freezes over in late October or early November and stays icebound until April or early May. Its largest tributary is the Menza River.